Hell's Half Acre VulkanHell's Half Acre is the easternmost and second largest of the young basaltic lava fields of the Snake River Plain, Idaho. It covers an area of about 400 sq km SW of Idaho Falls. The last eruptions occurred about 5200 years ago.
Beschreibung:Hell's Half Acre consists of a low basaltic lava shield with predominantly pahoehoe lava. Most eruptions took place from a 3-km-long, NW-SE trending vent system at the NW part of the field.
The summit vent area contains an irregular, elongate 0.8 x 0.3 km wide central caldera which contained a lava lake. There are about 10 circular pit craters on the lava lake and 2 prominent lava tube systems near the summit.
2 major lava flows, each about 5 km wide and 10 km long, extend to the south and SW along the flood plain of the Snake River and surround Morgans Pasture, a large kipuka (island spared by the lava flows). Interstate 15 highway crosses the SE margin of the lava field SW of the city of Idaho Falls.